News

Health Agency Addresses Antibiotic Resistance Issue

18 September 2013

US - A new report from the Centers for Disease Control & Prevention (CDC) prioritises the most threatening 'superbugs' in human medicine and outlines four core actions to halt resistance. The Center's role in preventing antibiotic resistance in food is included in the report.

Antibiotic Resistance Threats in the United States, 2013 is a snapshot of the complex problem of antibiotic resistance today and the potentially catastrophic consequences of inaction, according to the CDC.

The overriding purpose of this report, says CDC, is to increase awareness of the threat that antibiotic resistance poses and to encourage immediate action to address the threat. This document can serve as a reference for anyone looking for information about antibiotic resistance. It is specifically designed to be accessible to many audiences. For more technical information, references and links are provided.

This report covers bacteria causing severe human infections and the antibiotics used to treat those infections. In addition, Candida, a fungus that commonly causes serious illness, especially among hospital patients, is included because it, too, is showing increasing resistance to the drugs used for treatment. When discussing the pathogens included in this report, Candida will be included when referencing “bacteria” for simplicity.

Also, infections caused by the bacteria Clostridium difficile are also included in this report. Although C. difficile infections are not yet significantly resistant to the drugs used to treat them, most are directly related to antibiotic use and thousands of Americans are affected each year.

Drug resistance related to viruses such as HIV and influenza is not included, nor is drug resistance among parasites such as those that cause malaria. These are important problems but are beyond the scope of this report. The report consists of multiple one- or two-page summaries of cross-cutting and bacteria-specific antibiotic resistance topics.

The first section provides context and an overview of antibiotic resistance in the United States. In addition to giving a national assessment of the most dangerous antibiotic resistance threats, it summarizes what is known about the burden of illness, level of concern, and antibiotics left to defend against these infections. This first section also includes some basic background information, such as fact sheets about antibiotic safety and the harmful impact that resistance can have on high-risk groups, including those with chronic illnesses such as cancer.

CDC estimates that in the United States, more than two million people are sickened every year with antibiotic-resistant infections, with at least 23,000 dying as a result. The estimates are based on conservative assumptions and are likely minimum estimates. They are the best approximations that can be derived from currently available data.

Regarding level of concern, CDC has — for the first time — prioritised bacteria in this report into one of three categories: urgent, serious, and concerning.

Urgent threats

Clostridium difficile

Carbapenem-resistant Enterobacteriaceae (CRE)

Drug-resistant Neisseria gonorrhoeae

Serious threats

Multidrug-resistant Acinetobacter

Drug-resistant Campylobacter

Fluconazole-resistant Candida (a fungus)

Extended spectrum β-lactamase producing Enterobacteriaceae (ESBLs)

Vancomycin-resistant Enterococcus (VRE)

Multidrug-resistant Pseudomonas aeruginosa

Drug-resistant Non-typhoidal Salmonella

Drug-resistant Salmonella Typhimurium

Drug-resistant Shigella

Methicillin-resistant Staphylococcus aureus (MRSA)

Drug-resistant Streptococcus pneumoniae

Drug-resistant tuberculosis

Concerning threats

Vancomycin-resistant Staphylococcus aureus (VRSA)

Erythromycin-resistant Group A Streptococcus

Clindamycin-resistant Group B Streptococcus

The second section of the report describes what can be done to combat this growing threat, including information on current CDC initiatives.

Four core actions that fight the spread of antibiotic resistance are presented and explained, including:

preventing infections from occurring and preventing resistant bacteria from spreading

tracking resistant bacteria

improving the use of antibiotics, and

promoting the development of new antibiotics and new diagnostic tests for resistant bacteria.

The third section provides summaries of each of the bacteria in this report. These summaries can aid in discussions about each bacteria, how to manage infections, and implications for public health. They also highlight the similarities and differences among the many different types of infections.

This section also includes information about what groups such as states, communities, doctors, nurses, patients, and CDC can do to combat antibiotic resistance. Preventing the spread of antibiotic resistance can only be achieved with widespread engagement, especially among leaders in clinical medicine, healthcare leadership, agriculture and public health. Although some people are at greater risk than others, no one can completely avoid the risk of antibiotic-resistant infections. Only through concerted commitment and action will the nation ever be able to succeed in reducing this threat.

The first section of the CDC's report, entitled 'Preventing Infections, Preventing the Spread of Resistance', includes the following section of improving antibiotic use.

* "Antibiotics must be used judiciously in humans and animals because both uses contribute not only to the emergence but also the persistence and spread of antibiotic-resistant bacteria."

CDC’s Work to Prevent Antibiotic Resistance in Food

Each year, millions of people in the United States become sick from foodborne and other enteric (gastrointestinal) infections. While many of these infections are mild and do not require treatment, antibiotics can be lifesaving in severe infections. Antibiotic resistance compromises our ability to treat these infections and is a serious threat to public health.

Preventing resistant enteric infections requires a multifaceted approach and partnerships because bacteria that cause some infections, such as salmonellosis and campylobacteriosis, have animal reservoirs, while other bacteria, such as those that cause shigellosis and typhoid fever, have human reservoirs.

To prevent antibiotic-resistant foodborne infections, CDC works closely with state and local health departments; with the US Food and Drug Administration (FDA), which regulates antibiotics, many foods, animal feed, and other products; and with the U.S. Department of Agriculture (USDA), which regulates meat, poultry, and egg products.

Tracking antibiotic resistance

In 1996, the National Antimicrobial Resistance Monitoring System (NARMS) was established as a collaboration among CDC, FDA, USDA, and state and local public health departments. This national public health surveillance system tracks antibiotic resistance among Salmonella, Campylobacter, and other bacteria transmitted commonly through food. NARMS tests bacteria from humans (CDC), retail meats (FDA), and food-producing animals (USDA) in the United States.

Conduct research to better understand the emergence, persistence, and spread of antibiotic resistance.

Provide data that assist the FDA in making decisions about approving safe and effective antibiotic drugs for animals.

The CDC reference laboratory conducts antibiotic susceptibility testing on isolates from sporadic cases and outbreaks of illness. The lab also confirms and studies bacteria that have new antibiotic resistance patterns.

NARMS provides information about patterns of emerging resistance among enteric pathogens to stakeholders, including federal regulatory agencies, policymakers, consumer advocacy groups, industry, and the public, to guide public health prevention and policy efforts that protect people from resistant infections.

Improving antibiotic use

Antibiotics are widely used in food-producing animals, and according to data published by FDA, there are more kilograms of antibiotics sold in the United States for food-producing animals than for people. (http://www.fda.gov/downloads/ForIndustry/UserFees/AnimalDrugUserFeeActADUFA/UCM338170. pdf). This use contributes to the emergence of antibiotic-resistant bacteria in food-producing animals. Resistant bacteria in food-producing animals are of particular concern because these animals serve as carriers Resistant bacteria can contaminate the foods that come from those animals, and people who consume these foods can develop antibiotic-resistant infections.

Antibiotics must be used judiciously in humans and animals because both uses contribute not only to the emergence but also the persistence and spread of antibiotic-resistant bacteria.

Scientists around the world have provided strong evidence that antibiotic use in food-producing animals can harm public health through the following sequence of events:

Use of antibiotics in food-producing animals allows antibiotic-resistant bacteria to thrive while susceptible bacteria are suppressed or die.

Resistant bacteria can be transmitted from food-producing animals to humans through the food supply.

Resistant bacteria can cause infections in humans.

Infections caused by resistant bacteria can result in adverse health consequences for humans.

Because of the link between antibiotic use in food-producing animals and the occurrence of antibiotic-resistant infections in humans, antibiotics should be used in food-producing animals only under veterinary oversight and only to manage and treat infectious diseases, not to promote growth.